This invention relates to sound attenuation, and specifically to the reduction of machinery noise levels through use of acoustic blankets.
Growing environmental sound concerns and recognition that lengthy, unprotected exposure to high industrial noise levels can be detrimental to people have resulted in increased attention to reducing industrial noise. In many countries, particularly those in Europe, the allowable maximum noise levels that workers should be exposed to is regulated by law, through government promulgation of noise level criteria.
Recent years have seen the enactment of stringent regulatory requirements for acceptable noise levels for industrial machinery such that increasingly lower noise levels are being required. Because of the increased awareness of the harmful effects from high industrial noise levels and government regulations that establish acceptable noise levels in the work place, noise reduction has become an integral part of machinery safety. Noise abatement is a concern with, for example, generator-steam and gas turbine power plants. As demands for electricity increase, the power industry faces increasing challenges to build and operate efficient and quiet power generators, e.g. steam turbines, gas turbines, and electrical generators.
In an industrial environment, the types of equipment used often emits noise levels that register at high and potentially harmful decibel levels. In a power plant, noise may come from a variety of machine sources, such as generators, gas or steam turbines, fans, pumps, coolers, and other mechanical and electrical equipment, many of which may be in operation simultaneously. Individuals working in such an environment are often faced with the need to reduce the near and far field machinery noise levels. In an environment where individuals work in close proximity to the source(s) of machine noise, near field sound levels must be controlled in order to comply with noise regulating and avoid hearing damage to the workers. Where machine noise can reach areas that are near an industrial plant, it may be prudent to abate far field machine noise to acceptable levels and to avoid broadcasting neighboring communities.
There are several conventional methods available to reduce generator noise levels. These methods are handicapped by one shortcoming or another. Generally, all are overly costly. In one technique, a noise control housing enclosure covers the generator in its entirety. The cost for this enclosure is excessive. In another technique, barrier walls around a power generator constructed from steel are used to reduce generator noise. Such walls are built around the generator, leaving the top open. The cost for this type of noise reduction treatment is also expensive.
In a first embodiment, the invention is an acoustic blanket for an industrial machine comprising: a plurality of flexible panels, wherein each panel includes at least one layer of a fiber glass material, an outer casing of a chemically resistant material and an attachment for connecting the panel to an adjacent panel, and said plurality of flexible panels are each assigned a position in said blanket corresponding to a location on the industrial machine.
In a second embodiment, the invention is a system for reducing the sound in an industrial machine comprising: an acoustic blanket further comprising a quilt of interconnected flexible panels, wherein each panel includes at least one layer of a sound adsorbing material, an outer casing of a chemically resistant material and an attachment for connecting the panel to at least one adjacent panel, wherein each of said panels bears an indicia indicating a position of the panel in said blanket, and a securing device extending over said blanket to hold the blanket onto said machine.
In a third embodiment, the invention is a method for installing an industrial acoustic blanket on an industrial machine comprising: (a) forming flexible panels wherein each panel includes at least one layer of a sound adsorbing material, an outer casing of a chemically resistant material, and an attachment for connecting the panel to at least one adjacent panel; (b) marking each of said panel with an indicia indicating a position of the panel in said blanket corresponding to a location on the industrial machine; (c) positioning each of said panels the corresponding location of said industrial machine using the indicia to determine the proper location of the panel on the machine; (d) attaching the panels to adjacent panels of the blanket, and (e) securing the blanket to the machine.